A colony of primates, Macaca fascisularis, which has been infected with Strep. mutans and is being fed a diet rich in sucrose is being used to develop a vaccine against dental caries. Pneumococcal polysaccharides types II and IX, glucosyl transferase, and heat killed Strep. mutans cells have been administered to age matched monkeys intraductally or intramucosally with aluminum hydroxide as adjuvant. No protection was observed in the monkeys vaccinated using the pneumococcal polysaccharide or in the animals vaccinated intramucosally. Monkeys vaccinated with glucosyl transferase had fewer lesions than the other animals.